At the present time there are fruit transport systems for its discrimination and later size-grading integrated as components of electronic sizers able to differentiate fruit and scan its surface, in order to evaluate this according to quality parameters by optical selection of defects. Later on its equatorial diameter, weight and volume are calibrated and this is distributed by conveyors integrated in the sizer which send the fruit calibrated in this way to different zones for preparing and packing the product, by means of guide plates, selection hatches, jettison devices, amongst others. In the first of these cases two outlet conveyors are needed for each inlet conveyor, which requires an increase in the width, always unwanted and often not feasible through the spaces in this kind of installations being optimised. In the others, as the fruit falls by gravity, this causes an impact on at least one part of the fruit, either the suitable or the unsuitable fruit, which will in many cases make this burst and leave juice on the transport items.
The installation of the electronic type of sizer requires linear distribution of its structure and distribution conveyors perpendicular to this, spread over its whole length at minimum distances from each other, which entails major demands as regards the size of machinery and thus great expense and long payback periods as compared with conventional central sizing machines with tilting rollers.
In electronic sizing for the fruit and vegetable products as mentioned above, systems for transporting and differentiating fruit for its sizing and later distribution are used with similar technical solutions in most of the sizers currently available on the market.
The intention is nevertheless to prevent battering the fruit by means of a gentle selection at the unloading point at different heights.
The system used consists of a group of conveyors known as singulators, forming a set of parallel tracks, arranged in groups of two, and constituting a V shape, forming an angle of roughly 90°. The fruit from the processing line is transported one by one on these singulating conveyors. The dimensions of this first assembly depend on the production and manufacturer's requirements, usually being about five meters long.
After the singulator conveyors mentioned, there is a following module known as a differentiator, which is synchronised with the singulator conveyors. This is a set of chains which support twin cone or bobbin rollers (diabolos) on the sides, mounted in sets of two on their respective axles along their entire length.